Low power touch sensing during a sleep state of an electronic device

ABSTRACT

An electronic device is disclosed. The electronic device can sense touch on its touch screen while in a sleep state in a manner that allows the electronic device to respond to certain touch inputs, while consuming less power due to touch sensing than while in an awake state. For example, sensing touch during the sleep state can allow the electronic device to wake (e.g., transition from the sleep state to the awake state) in response to detecting a certain touch input (e.g., a tap or other touch input) on its touch screen while in the sleep state. Various ways for the electronic device to sense touch during the sleep state are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/180,537 (published as U.S. Publication No. 2021/0173466), filed onFeb. 19, 2021, which is a continuation of U.S. patent application Ser.No. 15/690,565 (issued as U.S. Pat. No. 10,928,881), filed on Aug. 30,2017, which claims benefit of U.S. Provisional Patent Application No.62/551,002, filed on Aug. 28, 2017, and U.S. Provisional PatentApplication No. 62/399,215, filed Sep. 23, 2016, which are herebyincorporated by reference in their entirety for all purposes.

FIELD OF THE DISCLOSURE

This relates generally to touch sensor panels, and more particularly, tosensing touch during a sleep state of an electronic device that includesa touch sensor panel.

BACKGROUND OF THE DISCLOSURE

Many types of input devices are presently available for performingoperations in a computing system, such as buttons or keys, mice,trackballs, joysticks, touch sensor panels, touch screens and the like.Touch screens, in particular, are becoming increasingly popular becauseof their ease and versatility of operation as well as their decliningprice. Touch screens can include a touch sensor panel, which can be aclear panel with a touch-sensitive surface, and a display device such asa liquid crystal display (LCD) that can be positioned partially or fullybehind the panel so that the touch-sensitive surface can cover at leasta portion of the viewable area of the display device. Touch screens canallow a user to perform various functions by touching the touch sensorpanel using a finger, stylus or other object at a location oftendictated by a user interface (UI) being displayed by the display device.In general, touch screens can recognize a touch and the position of thetouch on the touch sensor panel, and the computing system can theninterpret the touch in accordance with the display appearing at the timeof the touch, and thereafter can perform one or more actions based onthe touch. In the case of some touch sensing systems, a physical touchon the display is not needed to detect a touch. For example, in somecapacitive-type touch sensing systems, fringing electrical fields usedto detect touch can extend beyond the surface of the display, andobjects approaching near the surface may be detected near the surfacewithout actually touching the surface.

Capacitive touch sensor panels can be formed by a matrix ofsubstantially transparent or non-transparent conductive plates made ofmaterials such as Indium Tin Oxide (ITO). It is due in part to theirsubstantial transparency that capacitive touch sensor panels can beoverlaid on a display to form a touch screen, as described above. Sometouch screens can be formed by at least partially integrating touchsensing circuitry into a display pixel stackup (i.e., the stackedmaterial layers forming the display pixels).

SUMMARY OF THE DISCLOSURE

In some examples, the touch screens of the disclosure can be included inan electronic device, such as a mobile phone, a tablet computer or awearable device. It can be beneficial for the electronic device to sensetouch on its touch screen while in a sleep state in a manner that allowsthe electronic device to respond to certain touch inputs, whileconsuming less power due to touch sensing than while in an awake state.For example, sensing touch during the sleep state can allow theelectronic device to wake (e.g., transition from the sleep state to theawake state) in response to detecting a certain touch input (e.g., a tapor other touch input) on its touch screen while in the sleep state. Theexamples of the disclosure provide various ways for the electronicdevice to sense touch during the sleep state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D illustrate an example mobile telephone, an example mediaplayer, an example personal computer and an example tablet computer thatcan each include an exemplary touch screen according to examples of thedisclosure.

FIG. 2 is a block diagram of an example computing system thatillustrates one implementation of an example touch screen according toexamples of the disclosure.

FIG. 3A illustrates an exemplary touch sensor circuit corresponding to aself-capacitance touch node electrode and sensing circuit according toexamples of the disclosure.

FIG. 3B illustrates an exemplary touch sensor circuit corresponding to amutual-capacitance drive and sense line and sensing circuit according toexamples of the disclosure.

FIG. 4 illustrates an example configuration in which common electrodescan form portions of the touch sensing circuitry of a touch sensingsystem according to examples of the disclosure.

FIG. 5 illustrates an exemplary mutual capacitance touch screenconfiguration according to examples of the disclosure.

FIGS. 6A-6B illustrate exemplary touch sensing activity at an electronicdevice according to examples of the disclosure.

FIG. 7 illustrates an exemplary touch frame of an electronic device in asleep state according to examples of the disclosure.

FIGS. 8A-8B illustrate exemplary drive and/or sense line gangingaccording to examples of the disclosure.

FIG. 9 illustrates an exemplary touch frame of an electronic device in asleep state that includes conditional performance of touch scan stepsaccording to examples of the disclosure.

FIG. 10 illustrates an exemplary timeline of touch frames withintentional main scan triggering according to examples of thedisclosure.

FIG. 11 illustrates an exemplary touch screen in which the drivecircuitry and/or sense circuitry corresponding to edge regions of thetouch screen have been powered down according to examples of thedisclosure.

DETAILED DESCRIPTION

In the following description of examples, reference is made to theaccompanying drawings which form a part hereof, and in which it is shownby way of illustration specific examples that can be practiced. It is tobe understood that other examples can be used and structural changes canbe made without departing from the scope of the disclosed examples.

Some capacitive touch sensor panels can be formed by a matrix ofsubstantially transparent or non-transparent conductive plates made ofmaterials such as Indium Tin Oxide (ITO), and some touch screens can beformed by at least partially integrating touch sensing circuitry into adisplay pixel stackup (i.e., the stacked material layers forming thedisplay pixels). In some examples, the touch screens of the disclosurecan be included in an electronic device, such as a mobile phone, atablet computer or a wearable device. It can be beneficial for theelectronic device to sense touch on its touch screen while in a sleepstate in a manner that allows the electronic device to respond tocertain touch inputs, while consuming less power due to touch sensingthan while in an awake state. For example, sensing touch during thesleep state can allow the electronic device to wake (e.g., transitionfrom the sleep state to the awake state) in response to detecting acertain touch input (e.g., a tap or other touch input) on its touchscreen while in the sleep state. The examples of the disclosure providevarious ways for the electronic device to sense touch during the sleepstate.

FIGS. 1A-1D illustrate example systems in which a touch screen accordingto examples of the disclosure may be implemented. FIG. 1A illustrates anexample mobile telephone 136 that includes a touch screen 124. FIG. 1Billustrates an example digital media player 140 that includes a touchscreen 126. FIG. 1C illustrates an example personal computer 144 thatincludes a touch screen 128. FIG. 1D illustrates an example tabletcomputer 148 that includes a touch screen 130. It is understood that theabove touch screens can be implemented in other devices as well,including in wearable devices.

In some examples, touch screens 124, 126, 128 and 130 can be based onself-capacitance. A self-capacitance based touch system can include amatrix of small, individual plates of conductive material that can bereferred to as touch node electrodes (as described below with referenceto touch screen 220 in FIG. 2). For example, a touch screen can includea plurality of individual touch node electrodes, each touch nodeelectrode identifying or representing a unique location on the touchscreen at which touch or proximity (i.e., a touch or proximity event) isto be sensed, and each touch node electrode being electrically isolatedfrom the other touch node electrodes in the touch screen/panel. Such atouch screen can be referred to as a pixelated self-capacitance touchscreen, though it is understood that in some examples, the touch nodeelectrodes on the touch screen can be used to perform scans other thanself-capacitance scans on the touch screen (e.g., mutual capacitancescans). During operation, a touch node electrode can be stimulated withan AC waveform, and the self-capacitance to ground of the touch nodeelectrode can be measured. As an object approaches the touch nodeelectrode, the self-capacitance to ground of the touch node electrodecan change. This change in the self-capacitance of the touch nodeelectrode can be detected and measured by the touch sensing system todetermine the positions of multiple objects when they touch, or come inproximity to, the touch screen. In some examples, the electrodes of aself-capacitance based touch system can be formed from rows and columnsof conductive material, and changes in the self-capacitance to ground ofthe rows and columns can be detected, similar to above. In someexamples, a touch screen can be multi-touch, single touch, projectionscan, full-imaging multi-touch, capacitive touch, etc.

In some examples, touch screens 124, 126, 128 and 130 can be based onmutual capacitance. A mutual capacitance based touch system can includedrive and sense lines that may cross over each other on differentlayers, or may be adjacent to each other on the same layer. The crossingor adjacent locations can be referred to as touch nodes. Duringoperation, the drive line can be stimulated with an AC waveform and themutual capacitance of the touch node can be measured. As an objectapproaches the touch node, the mutual capacitance of the touch node canchange. This change in the mutual capacitance of the touch node can bedetected and measured by the touch sensing system to determine thepositions of multiple objects when they touch, or come in proximity to,the touch screen.

FIG. 2 is a block diagram of an example computing system 200 thatillustrates one implementation of an example self-capacitance touchscreen 220 according to examples of the disclosure. It is understoodthat computing system 200 can instead analogously include a mutualcapacitance touch screen. Computing system 200 can be included in, forexample, mobile telephone 136, digital media player 140, personalcomputer 144, tablet computer 148, or any mobile or non-mobile computingdevice that includes a touch screen, including a wearable device.Computing system 200 can include a touch sensing system including one ormore touch processors 202, peripherals 204, a touch controller 206, andtouch sensing circuitry (described in more detail below). Peripherals204 can include, but are not limited to, random access memory (RAM) orother types of memory or storage, watchdog timers and the like. Touchcontroller 206 can include, but is not limited to, one or more sensechannels 208 and channel scan logic 210. Channel scan logic 210 canaccess RAM 212, autonomously read data from sense channels 208 andprovide control for the sense channels. In addition, channel scan logic210 can control sense channels 208 to generate stimulation signals atvarious frequencies and phases that can be selectively applied to thetouch nodes of touch screen 220, as described in more detail below. Insome examples, touch controller 206, touch processor 202 and peripherals204 can be integrated into a single application specific integratedcircuit (ASIC), and in some examples can be integrated with touch screen220 itself.

Touch screen 220 can include touch sensing circuitry that can include acapacitive sensing medium having a plurality of electrically isolatedtouch node electrodes 222 (e.g., a pixelated self-capacitance touchscreen). Touch node electrodes 222 can be coupled to sense channels 208in touch controller 206, can be driven by stimulation signals from thesense channels through drive/sense interface 225, and can be sensed bythe sense channels through the drive/sense interface as well, asdescribed above. Labeling the conductive plates used to detect touch(i.e., touch node electrodes 222) as “touch node” electrodes can beparticularly useful when touch screen 220 is viewed as capturing an“image” of touch (e.g., a “touch image”). In other words, after touchcontroller 206 has determined an amount of touch detected at each touchnode electrode 222 in touch screen 220, the pattern of touch nodeelectrodes in the touch screen at which a touch occurred can be thoughtof as a touch image (e.g., a pattern of fingers touching the touchscreen).

Computing system 200 can also include a host processor 228 for receivingoutputs from touch processor 202 and performing actions based on theoutputs. For example, host processor 228 can be connected to programstorage 232 and a display controller, such as an LCD driver 234. The LCDdriver 234 can provide voltages on select (e.g., gate) lines to eachpixel transistor and can provide data signals along data lines to thesesame transistors to control the pixel display image as described in moredetail below. Host processor 228 can use LCD driver 234 to generate adisplay image on touch screen 220, such as a display image of a userinterface (UI), and can use touch processor 202 and touch controller 206to detect a touch on or near touch screen 220. The touch input can beused by computer programs stored in program storage 232 to performactions that can include, but are not limited to, moving an object suchas a cursor or pointer, scrolling or panning, adjusting controlsettings, opening a file or document, viewing a menu, making aselection, executing instructions, operating a peripheral deviceconnected to the host device, answering a telephone call, placing atelephone call, terminating a telephone call, changing the volume oraudio settings, storing information related to telephone communicationssuch as addresses, frequently dialed numbers, received calls, missedcalls, logging onto a computer or a computer network, permittingauthorized individuals access to restricted areas of the computer orcomputer network, loading a user profile associated with a user'spreferred arrangement of the computer desktop, permitting access to webcontent, launching a particular program, encrypting or decoding amessage, and/or the like. Host processor 228 can also perform additionalfunctions that may not be related to touch processing.

Note that one or more of the functions described herein, including theconfiguration of switches, can be performed by firmware stored in memory(e.g., one of the peripherals 204 in FIG. 2) and executed by touchprocessor 202, or stored in program storage 232 and executed by hostprocessor 228. The firmware can also be stored and/or transported withinany non-transitory computer-readable storage medium for use by or inconnection with an instruction execution system, apparatus, or device,such as a computer-based system, processor-containing system, or othersystem that can fetch the instructions from the instruction executionsystem, apparatus, or device and execute the instructions. In thecontext of this document, a “non-transitory computer-readable storagemedium” can be any medium (excluding signals) that can contain or storethe program for use by or in connection with the instruction executionsystem, apparatus, or device. The computer-readable storage medium caninclude, but is not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus or device,a portable computer diskette (magnetic), a random access memory (RAM)(magnetic), a read-only memory (ROM) (magnetic), an erasableprogrammable read-only memory (EPROM) (magnetic), a portable opticaldisc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory suchas compact flash cards, secured digital cards, USB memory devices,memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport medium can include, but is not limited to, anelectronic, magnetic, optical, electromagnetic or infrared wired orwireless propagation medium.

FIG. 3A illustrates an exemplary touch sensor circuit 300 correspondingto a self-capacitance touch node electrode 302 and sensing circuit 314according to examples of the disclosure. Touch node electrode 302 cancorrespond to touch node electrode 222. Touch node electrode 302 canhave an inherent self-capacitance to ground associated with it, and alsoan additional self-capacitance to ground that is formed when an object,such as finger 305, is in proximity to or touching the electrode. Thetotal self-capacitance to ground of touch node electrode 302 can beillustrated as capacitance 304. Touch node electrode 302 can be coupledto sensing circuit 314. Sensing circuit 314 can include an operationalamplifier 308, feedback resistor 312 and feedback capacitor 310,although other configurations can be employed. For example, feedbackresistor 312 can be replaced by a switched capacitor resistor in orderto minimize a parasitic capacitance effect that can be caused by avariable feedback resistor. Touch node electrode 302 can be coupled tothe inverting input (−) of operational amplifier 308. An AC voltagesource 306 (Vac) can be coupled to the non-inverting input (+) ofoperational amplifier 308. Touch sensor circuit 300 can be configured tosense changes in the total self-capacitance 304 of the touch nodeelectrode 302 induced by a finger or object either touching or inproximity to the touch sensor panel. Output 320 can be used by aprocessor to determine the presence of a proximity or touch event, orthe output can be inputted into a discrete logic network to determinethe presence of a proximity or touch event.

FIG. 3B illustrates an exemplary touch sensor circuit 350 correspondingto mutual-capacitance drive 322 and sense 326 lines and sensing circuit314 according to examples of the disclosure. Drive line 322 can bestimulated by stimulation signal 306 (e.g., an AC voltage signal).Stimulation signal 306 can be capacitively coupled to sense line 326through mutual capacitance 324 between drive line 322 and the senseline. When a finger or object 305 approaches the touch node created bythe intersection of drive line 322 and sense line 326, mutualcapacitance 324 can be altered. This change in mutual capacitance 324can be detected to indicate a touch or proximity event at the touchnode, as described previously and below. The sense signal coupled ontosense line 326 can be received by sensing circuit 314. Sensing circuit314 can include operational amplifier 308 and at least one of a feedbackresistor 312 and a feedback capacitor 310. FIG. 3B illustrates a generalcase in which both resistive and capacitive feedback elements areutilized. The sense signal (referred to as Vin) can be inputted into theinverting input of operational amplifier 308, and the non-invertinginput of the operational amplifier can be coupled to a reference voltageVref. Operational amplifier 308 can drive its output to voltage Vo tokeep Vin substantially equal to Vref, and can therefore maintain Vinconstant or virtually grounded. A person of skill in the art wouldunderstand that in this context, equal can include deviations of up to15%. Therefore, the gain of sensing circuit 314 can be mostly a functionof the ratio of mutual capacitance 324 and the feedback impedance,comprised of resistor 312 and/or capacitor 310. The output of sensingcircuit 314 Vo can be filtered and heterodyned or homodyned by being fedinto multiplier 328, where Vo can be multiplied with local oscillator330 to produce Vdetect. Vdetect can be inputted into filter 332. Oneskilled in the art will recognize that the placement of filter 332 canbe varied; thus, the filter can be placed after multiplier 328, asillustrated, or two filters can be employed: one before the multiplierand one after the multiplier. In some examples, there can be no filterat all. The direct current (DC) portion of Vdetect can be used todetermine if a touch or proximity event has occurred.

Referring back to FIG. 2, in some examples, touch screen 220 can be anintegrated touch screen in which touch sensing circuit elements of thetouch sensing system can be integrated into the display pixel stackupsof a display. The circuit elements in touch screen 220 can include, forexample, elements that can exist in LCD or other displays (e.g., organiclight emitting diode (OLED) displays, plasma display panel (PDP)displays, electroluminescent displays (ELD), light-emitting diode (LED)displays, etc.), such as one or more pixel transistors (e.g., thin filmtransistors (TFTs)), gate lines, data lines, pixel electrodes and commonelectrodes. In a given display pixel, a voltage between a pixelelectrode and a common electrode can control a luminance of the displaypixel. The voltage on the pixel electrode can be supplied by a data linethrough a pixel transistor, which can be controlled by a gate line. Itis noted that circuit elements are not limited to whole circuitcomponents, such as a whole capacitor, a whole transistor, etc., but caninclude portions of circuitry, such as only one of the two plates of aparallel plate capacitor.

FIG. 4 illustrates an example configuration in which common electrodes402 can form portions of the touch sensing circuitry of a touch sensingsystem—in some examples of this disclosure, the common electrodes canform touch node electrodes used to detect a touch image on touch screen400, as described above. Each common electrode 402 can include aplurality of display pixels 401, and each display pixel 401 can includea portion of a common electrode 402, which can be a circuit element ofthe display system circuitry in the display pixel stackup (i.e., thestacked material layers forming the display pixels) of the displaypixels of some types of LCDs or other displays (e.g., organic lightemitting diode (OLED) displays, plasma display panel (PDP) displays,electroluminescent displays (ELD), light-emitting diode (LED) displays,etc.)—in other words, the common electrodes can operate as part of thedisplay system to display a display image on touch screen 400. WhileFIG. 4 illustrates a pixelated touch screen 400 (e.g., a pixelatedself-capacitance touch screen), it is understood that drive and/or senseelectrodes of a mutual capacitance touch screen can function as commonelectrodes of an integrated touch screen in an analogous manner tocommon electrodes 402 in touch screen 400.

In the example shown in FIG. 4, each common electrode 402 can serve as amulti-function circuit element that can operate as display circuitry ofthe display system of touch screen 400 and can also operate as touchsensing circuitry of the touch sensing system. Specifically, each commonelectrode 402 can operate as a common electrode of the display circuitryof the touch screen 400 (e.g., during a display phase), as describedabove, and can also operate as a touch node electrode of the touchsensing circuitry of the touch screen (e.g., during a touch sensingphase). Other circuit elements of touch screen 400 can also form part ofthe touch sensing circuitry. More specifically, in some examples, duringthe touch sensing phase, a gate line can be connected to a power supply,such as a charge pump, that can apply a voltage to maintain TFTs indisplay pixels included in a common electrode 402 in an “off” state.Stimulation signals can be applied to the common electrode 402. Changesin the total self-capacitance of the common electrode 402 can be sensedthrough one or more operational amplifiers, as previously discussed. Thechanges in the total self-capacitance of the common electrode 402 candepend on the proximity of an object, such as finger 305, to the commonelectrode. In this way, the measured changes in total self-capacitanceof the common electrode 402 can provide an indication of touch on ornear the touch screen. A mutual capacitance touch screen can similarlybe implemented in which common electrodes can form portions of the touchsensing circuitry of the mutual capacitance touch screen. For examplethe common electrodes can form drive or sense lines used to detect atouch image on the touch screen, as described above.

In general, each of the touch sensing circuit elements may be either amulti-function circuit element that can form part of the touch sensingcircuitry and can perform one or more other functions, such as formingpart of the display circuitry, or may be a single-function circuitelement that can operate as touch sensing circuitry only. Similarly,each of the display circuit elements may be either a multi-functioncircuit element that can operate as display circuitry and perform one ormore other functions, such as operating as touch sensing circuitry, ormay be a single-function circuit element that can operate as displaycircuitry only. Therefore, in some examples, some of the circuitelements in the display pixel stackups can be multi-function circuitelements and other circuit elements may be single-function circuitelements. In other examples, all of the circuit elements of the displaypixel stackups may be single-function circuit elements.

In addition, although examples herein may describe the display circuitryas operating during a display phase, and describe the touch sensingcircuitry as operating during a touch sensing phase, it should beunderstood that a display phase and a touch sensing phase may beoperated at the same time, e.g., partially or completely overlapping, orthe display phase and touch sensing phase may operate at differenttimes. Also, although examples herein describe certain circuit elementsas being multi-function and other circuit elements as beingsingle-function, it should be understood that the circuit elements arenot limited to the particular functionality in other examples. In otherwords, a circuit element that is described in one example herein as asingle-function circuit element may be configured as a multi-functioncircuit element in other examples, and vice versa.

The common electrodes 402 (i.e., touch node electrodes) and displaypixels 401 of FIG. 4 are shown as rectangular or square regions on touchscreen 400. However, it is understood that the common electrodes 402 anddisplay pixels 401 are not limited to the shapes, orientations, andpositions shown, but can include any suitable configurations accordingto examples of the disclosure. Further, the examples of the disclosurewill be provided in the context of a touch screen, but it is understoodthat the examples of the disclosure can similarly be implemented in thecontext of a touch sensor panel.

As previously mentioned, in some examples, a touch screen of thedisclosure can be a mutual capacitance touch screen. FIG. 5 illustratesan exemplary mutual capacitance touch screen 500 configuration accordingto examples of the disclosure. Touch screen 500 can include rowelectrodes 522 and column electrodes 526 that intersect with rowelectrodes 522. In some examples, row electrodes 522 can be driveelectrodes of mutual capacitance touch screen 500 (e.g., correspondingto drive lines 322 in FIG. 3B), and column electrodes 526 can be senseelectrodes of mutual capacitance touch screen 500 (e.g., correspondingto sense lines 326 in FIG. 3B)—as such, row electrodes 522 can bereferred to as drive electrodes, and column electrodes 526 can bereferred to as sense electrodes. The intersections of drive electrodes522 and sense electrodes 526 can form touch nodes 502, which can eachrepresent a position on touch screen 500 at which an amount of touch canbe sensed to capture a “touch image” at touch screen 500. In someexamples, drive electrodes 522 can be driven by corresponding drivecircuitry 506 (also referred to as “transmit channels,” andcorresponding to stimulation signal 306 in FIG. 3B), and senseelectrodes 526 can be sensed by corresponding sense circuitry 514 (alsoreferred to as “receive channels,” and corresponding to sensing circuit314 in FIG. 3B) to capture the “touch image” at touch screen, asdescribed previously in this disclosure. In some examples, drivecircuitry 506 can include any suitable circuitry for driving driveelectrodes 522 with a stimulation signal (e.g., an AC voltage), such asan operational amplifier.

In some examples, the touch screens of the disclosure can be included inan electronic device, such as a mobile phone, a tablet computer or awearable device. When the electronic device is in an awake state (e.g.,a state in which its display and/or other components are turned on), theelectronic device can sense touch on its touch screen in the mannersdescribed above. When the electronic device is in a sleep state (e.g., alow-power state in which its display and/or other components are turnedoff), in some examples, the electronic device may not sense touch on itstouch screen; for example, the electronic device may turn off its driveand/or sense circuitry (e.g., as described in FIGS. 3A-3B) while in thesleep state to conserve power. However, in some examples, it can bebeneficial for the electronic device to sense touch on its touch screenwhile in the sleep state in a manner that allows the electronic deviceto respond to certain touch inputs, while consuming less power due totouch sensing than while in the awake state. For example, sensing touchduring the sleep state can allow the electronic device to wake (e.g.,transition from the sleep state to the awake state) in response todetecting a certain touch input (e.g., a tap or other touch input) onits touch screen while in the sleep state. In some examples, theelectronic device may only wake in response to detecting certain touchinputs (e.g., a tap) during the sleep state, and may not wake inresponse to detecting other touch inputs (e.g., a swipe, or a longpress) during the sleep state. The examples of the disclosure providevarious ways for the electronic device to sense touch during the sleepstate. It should be noted that the examples of the disclosure will beprovided in the context of a touch screen, but it is understood that theexamples of the disclosure can similarly be implemented in the contextof a touch sensor panel.

While the examples of the disclosure are described as occurring during a“sleep state” or an “awake state” of the electronic device, in someexamples, the electronic device can have more than two states ofoperation. For example, the electronic device can have an active stateand a plurality of low-power states, each corresponding to and defininga different manner of operation for the electronic device. In the activestate, a display of the electronic device (e.g., the display componentof the touch screen of the electronic device) can be active (e.g.,displaying one or more images), and processing circuitry associated withsensing touch on the touch screen of the electronic device can beoperating at a given state of readiness (e.g., touch controller 206and/or touch processor 202 can be powered on at full power operation).In some examples, such an active state can correspond to the “awakestate” described in this disclosure.

During a first low-power state (or a plurality of first low-powerstates) of the electronic device, some of the processing circuitryassociated with sensing touch on the touch screen of the electronicdevice can be disabled or in a reduced-activity/reduced-power state(e.g., touch controller 206 and/or touch processor 202 can be disabledor in reduced-power operation), though the display of the electronicdevice (e.g., the display component of the touch screen of theelectronic device) can remain active. In some examples, the electronicdevice can transition from the active state to the first low-power statein response to detecting an amount of touch on the touch screen that isless than a first threshold amount of touch for longer than a firstthreshold time.

During a second low-power state (or a plurality of second low-powerstates) of the electronic device, some of the processing circuitryassociated with sensing touch on the touch screen of the electronicdevice can be disabled or in a reduced-activity/reduced-power state(e.g., touch controller 206 and/or touch processor 202 can be disabledor in reduced-power operation), and some additional hardware in theelectronic device can additionally be disabled or in areduced-activity/reduced-power state (e.g., this additional hardwarecould have been enabled or in a normal-activity/normal-power stateduring the first low-power state). In the second low-power state, thedisplay of the electronic device (e.g., the display component of thetouch screen of the electronic device) can be disabled. In someexamples, the electronic device can transition from the first low-powerstate to the second low-power state in response to detecting an amountof touch on the touch screen that is less than a second threshold amountof touch for longer than a second threshold time. Additionally oralternatively, the electronic device can enter the second low-powerstate (e.g., from the first low-power state or the active state) inresponse to a command received from the system or from a user of theelectronic device. For example, the user can press a specific button onthe electronic device, or can completely cover, with their hand, thetouch screen of the electronic device, to transition the electronicdevice to the second low-power state. In some examples, such a secondlow-power state can correspond to the “sleep state” described in thisdisclosure. Further, in some examples, the second low-power state caninclude a plurality of sub-states depending on whether certain hardwarecomponents of the electronic device are operating; for example, if theelectronic device is playing audio through speakers, the electronicdevice can be in a first sub-state of the second low-power state, and ifthe electronic device is playing the audio through headphones/aheadphone jack rather than the speakers, the electronic device can be ina second sub-state of the second low-power state. The state/sub-state inwhich the electronic device is currently operating (e.g., the activestate, the first low-power state, the second low-power state and/or thesub-states of the second low-power state) can impact various aspects oftouch scanning performed by the electronic device, as will be describedin this disclosure. Further, any of the examples of the disclosure thatare described herein as occurring during the “sleep state” can occurduring one or more of the low-power states described above (e.g., thefirst low-power state, the second low-power state, specific sub-statesof the second low-power state, etc.), and any of the examples of thedisclosure that are described herein as occurring during the “awakestate” can occur during the active state described above.

FIGS. 6A-6B illustrate exemplary touch sensing activity at an electronicdevice according to examples of the disclosure. In FIG. 6A, during sleepstate 602, the electronic device may not perform any touch sensing atits touch screen, as described above. When the electronic devicetransitions to awake state 604 (e.g., at transition 606 corresponding tosome input at the electronic device for waking the electronic device,other than a touch input on its touch screen), the electronic device canperform touch sensing at its touch screen during touch frames T_(A) 608.Touch frames T_(A) 608 can correspond to periods of time during whichthe electronic device can perform one or more touch sensing-relatedfunctions, such as driving drive electrodes and/or sensing senseelectrodes on the touch screen of the electronic device.

In FIG. 6B, the electronic device can perform touch sensing at its touchscreen during awake state 604 as described with reference to FIG. 6A.However, during sleep state 602, instead of not performing touch sensingas in FIG. 6A, the electronic device can perform touch sensing at itstouch screen during touch frames T_(S) 610. Touch frames T_(S) 610 canbe the same or different than touch frames T_(A) 608 (e.g., the touchsensing-related functions that the electronic device performs duringtouch frames T_(S) 610 can be the same or different than the touchsensing-related functions that the electronic device performs duringtouch frames T_(A) 608). Because the electronic device in FIG. 6B canperform touch sensing during sleep state 602, the electronic device cansense touch on its touch screen during sleep state 602, and transition606 can correspond to a touch input (e.g., a tap) on the touch screen ofthe electronic device for waking the electronic device. This disclosureprovides various exemplary details of touch frames T_(S) 610 and/or howthey can compare to touch frames T_(A) 608, below. It should be notedthat the examples of the disclosure have been provided in the context ofa touch screen, but it is understood that the examples of the disclosurecan similarly be implemented in the context of a touch sensor panel.Further, awake state 604 can correspond to an active state of theelectronic device, and sleep state 602 can correspond to a firstlow-power state or a second low-power state of the electronic device, insituations in which the electronic device has an active state and aplurality of low-power states, as previously described.

FIG. 7 illustrates an exemplary touch frame T_(S) 710 of an electronicdevice in a sleep state according to examples of the disclosure. Touchframe T_(S) 710 can correspond to touch frames T_(S) 610 in FIG. 6B, andcan include a plurality of sub-frames. Specifically, touch frame T_(S)710 can include initialization frame T_(init) 712 during which varioustouch-related circuitry in the touch screen can be initialized andprepared for touch scanning. For example, a touch processor and/orcontroller (e.g., 202 and 206 in FIG. 2), drive circuitry (e.g., 306 inFIG. 3B) and/or sense circuitry (e.g., 314 in FIGS. 3A-3B) can beinitialized during T_(init) 712.

Touch frame T_(S) 710 can also include touch measurement frame T_(burst)714 during which touch can be sensed on the touch screen. In someexamples T_(burst) 714 can follow immediately after T_(init) 712, thoughother configurations are also possible. During T_(burst) 714, theelectronic device can perform active hardware-based scanning of itstouch screen to collect touch data. In some examples, T_(burst) 714 caninclude a number of scan steps. For example, T_(burst) 714 can include aspectral analysis scan step SPA 720 during which the electronic devicecan scan its touch screen with different touch sensing signals havingdifferent frequencies in order to determine one or more frequencies atwhich touch sensing can be least affected by noise. Based on the resultsof SPA 720, the electronic device can scan for touch at its touch screenduring scan steps SS1 722A, SS2 722B, SS(N−1) 722(N−1) and SSN 722N(referred to collectively as scan steps 722). During scan steps 722, theelectronic device can scan its touch screen for touch using the one ormore frequencies that it identified as low-noise frequencies during SPA720. For example, during SS1 722A, the electronic device can, usingdrive circuitry 506 in FIG. 5, stimulate drive electrodes 522 with afirst set of stimulation signals while sensing sense electrodes 526using sense circuitry 514. Similarly, during SS2 722B, the electronicdevice can, using drive circuitry 506 in FIG. 5, stimulate driveelectrodes 522 with a second set of stimulation signals while sensingsense electrodes 526 using sense circuitry 514. After N scan steps, theelectronic device can have sensed sufficient touch data (e.g., via sensecircuitry 514) to determine an image of touch on its touch screen. Insome examples, the number of scan steps 722 can correspond to the numberof discrete drive circuitry (or transmit channels) or drive electrodes522 included in the touch screen; for example, in FIG. 5, touch screen500 can include ten transmit channels 506 and ten corresponding driveelectrodes 522, and T_(S) 710 can include ten scan steps 722 thatcorrespond, respectively, to those ten transmit channels 506 and tendrive electrodes 522.

During T_(fp) 716, the electronic device can process the touch datacollected during scan steps 722 to determine whether a particular touchinput for waking the electronic device has been detected on the touchscreen. For example, the electronic device can determine whether a taphas been detected on the touch screen. If the particular touch input forwaking the electronic device has been detected on the touch screen, theelectronic device can transition to the awake state (e.g., as describedwith reference to FIG. 6B). If the particular touch input for waking theelectronic device was not detected on the touch screen (e.g., no touchinput was detected on the touch screen, or the touch input that wasdetected on the touch screen is not the particular touch input forwaking the electronic device), the electronic device can remain in thesleep state, and the remainder of touch frame T_(S) 710 can comprisesleep frame T_(sleep) 718 during which no touch sensing may be performedon the touch screen. The electronic device can then sense touch at itstouch screen in accordance with T_(S) 710 when the next touch frameT_(S) is executed.

In some examples, the lengths of scan steps 722 (i.e., the “integrationtime”) in touch frames T_(S) 710 during the sleep state can be shorterthan the lengths of corresponding scan steps that can be included intouch frames T_(A) 608 in the awake state. Specifically, touch sensingduring the sleep state of the electronic device (e.g., to detect apredetermined gesture to wake the electronic device, such as a tap) maynot require as much accuracy and/or may not be as impacted by noise astouch sensing during the awake state. Therefore, scan steps in the sleepstate can be shorter than scan steps in the awake state whilemaintaining satisfactory touch sensing performance. For example, touchframes T_(A) 608 in the awake state of the electronic device can includethe same number of scan steps for sensing touch on the touch screen asdo touch frames T_(S) 710 in the sleep state of the electronic device,and can, like in the sleep state, correspond to the number of discretedrive circuitry (or transmit channels) and/or drive electrodes 522included in the touch screen. Thus, in some examples, each scan step inthe awake state can have a corresponding scan step in the sleep state,the scan details of which can be the same (e.g., scan steps during whichthe same drive circuitry is operated). However, as mentioned above, insome examples, the lengths of the scan steps in the awake state can belonger (e.g., 150 μs) than the lengths of the scan steps 722 in touchframes T_(S) 710 in the sleep state (e.g., 20 μs, 50 μs). In this way,power consumption for touch sensing during the sleep state can bereduced while maintaining the ability to detect the predeterminedgesture (e.g., a tap) on the touch screen to wake the electronic device.In some examples, the length of each scan step 710 in the sleep statecan be shorter than the length of each scan step in the awake state. Insome examples, the average length of the scan steps in the sleep statecan be shorter than the average length of the scan steps in the awakestate. In some examples, the length of a given scan step in the sleepstate can be shorter than the length of that same corresponding scanstep in the awake state (e.g., the first scan step in the sleep statecan be shorter than the first scan step in the awake state, the secondscan step in the sleep state can be shorter than the second scan step inthe awake state, etc.) In examples in which the electronic device has anactive state and a plurality of low-power states, as previouslydescribed, scan steps in the second low-power state can be shorter thanscan steps in the first low-power state, which can be shorter than scansteps in the active state, analogous to as described above.

In some examples, the electronic device can dynamically alter thelengths of scan steps 722 in touch frame T_(S) 710 during the sleepstate (and/or during the first low-power state, the second low-powerstate, etc., in situations in which the electronic device has an activestate and a plurality of low-power states, as previously described). Forexample, initially, the electronic device can utilize scan steps 722that have an initial, short length, such as 20 μs (e.g., shorter thanthe length of scan steps in the awake state). Using these scan steps 722with the initial, short lengths, the electronic device can sense touchon its touch screen in the sleep state. In some examples, if touchactivity is detected on the touch screen, the electronic device canincrease the lengths of scan steps 722 to a value that is greater thanthe initial, short length to improve its ability to determine whetherthe touch activity is a tap or other input for waking the device (e.g.,from 20 μs to 50 μs, or from 20 μs to a length that is equal to orgreater than the length of scan steps in the awake state). Using thesescan steps 722 with increased lengths, the electronic device can sensetouch on its touch screen until it determines whether to transition tothe awake state in response to the touch activity.

In some examples, the electronic device can evaluate the signal-to-noiseratio of the resulting touch data before increasing the lengths of scansteps 722. Specifically, as above, the electronic device can initiallyutilize scan steps 722 that have an initial, short length, such as 20 μs(e.g., shorter than the length of scan steps in the awake state). Iftouch activity is detected on the touch screen, the electronic devicecan determine whether the resulting touch data has a sufficiently highsignal-to-noise ratio such that the device is able to identify the touchactivity, and determine whether it is a predetermined gesture to wakethe electronic device. If the electronic device is able to identify thetouch activity, then the electronic device can maintain the lengths ofscan steps 722, as is. However, if the resulting touch data has aninsufficiently high signal-to-noise ratio such that the electronicdevice is unable to identify the touch activity, the electronic devicecan gradually or incrementally increase the lengths of scan steps 722(e.g., from 20 μs to 30 μs, from 30 μs to 40 μs, etc.) until theresulting touch data has a sufficiently high signal-to-noise ratio suchthat the device is able to identify the touch activity on the touchscreen. In some examples, the increased lengths of scan steps 722 canremain less than the lengths of scan steps in the awake state, while inother examples, the increased lengths of scan steps 722 can match orexceed the lengths of scan steps in the awake state. Once the electronicdevice is able to identify the touch activity on the touch screen, itcan take appropriate action (e.g., wake the electronic device, becausethe touch activity corresponds to the predetermined gesture to wake theelectronic device, or maintain the electronic device in the sleep state,because the touch activity does not correspond to the predeterminedgesture to wake the electronic device), and in the next touch frameT_(S) 710 during the sleep state, the electronic device can return toutilizing the scan steps 722 that have the initial, short length, suchas 20 μs. The electronic device can, then, repeat the above whensubsequent touch activity is detected on the touch screen. In someexamples, the above-described signal-to-noise ratio-based scan lengthadjustments can occur in the first low-power state, the second low-powerstate, etc., in situations in which the electronic device has an activestate and a plurality of low-power states, as previously described.

In some examples, in addition or alternatively to adjusting the lengthsof scan steps 722 based on touch activity, as described above, theelectronic device can adjust the lengths of scan steps 722 based on theresults of SPA 720. For example, in operation, the electronic device canhave the ability to sense touch at a given set of touch sensingfrequencies (e.g., three, five or ten different touch sensingfrequencies from which the electronic device can select). If the scan ofthe touch screen during SPA 720 indicates that noise at the varioustouch sensing frequencies of the electronic device is above a noisethreshold, the electronic device can increase the lengths of scan steps722 in order to improve the signal-to-noise ratio of the resulting touchdata. In some examples, the electronic device can gradually orincrementally increase the lengths of scan steps 722 (e.g., from 20 μsto 30 μs, from 30 μs to 40 μs, etc.) until the resulting touch data hasa sufficiently high signal-to-noise ratio such that the device is ableto identify the touch activity on the touch screen. In some examples,the electronic device can directly increase the lengths of scan steps722 to a specified amount based on the results of SPA 720. For example,if the SPA 720 scan indicates noise of a first amount, the electronicdevice can increase the lengths of scan steps 722 to a first length, andif the SPA 720 scan indicates noise of a second amount, greater than thefirst amount, the electronic device can increase the lengths of scansteps 722 to a second length, greater than the first length. In someexamples, the increased lengths of scan steps 722 can remain less thanthe lengths of scan steps in the awake state, while in other examples,the increased lengths of scan steps 722 can match or exceed the lengthsof scan steps in the awake state. Once the electronic device is able toidentify the touch activity on the touch screen, it can take appropriateaction (e.g., wake the electronic device, because the touch activitycorresponds to the predetermined gesture to wake the electronic device,or maintain the electronic device in the sleep state, because the touchactivity does not correspond to the predetermined gesture to wake theelectronic device), and in the next touch frame T_(S) 710 during thesleep state, the electronic device can return to utilizing the scansteps 722 that have the initial, short length, such as 20 μs. Theelectronic device can, then, repeat the above when subsequent SPA 720scans are performed in subsequent touch frames T_(S) 710 in the sleepstate. In some examples, the above-described SPA 720-based scan lengthadjustments can occur in the first low-power state, the second low-powerstate, etc., in situations in which the electronic device has an activestate and a plurality of low-power states, as previously described.

In some examples, in addition or alternatively to adjusting the lengthsof scan steps 722 based on touch activity and/or the results of SPA 720,as described above, the electronic device can adjust the lengths of scansteps 722 based on power considerations. For example, the electronicdevice can utilize scan steps 722 of the shortest length possible (e.g.,to reduce power consumption) while maintaining sufficient touch sensingperformance (e.g., maintaining a signal-to-noise ratio that is greaterthan a threshold ratio, maintaining a touch signal value that is greaterthan a touch signal value threshold, etc.). It should be noted that theexamples of the disclosure have been provided in the context of a touchscreen, but it is understood that the examples of the disclosure cansimilarly be implemented in the context of a touch sensor panel.Further, in some examples, the electronic device can adjust the lengthsof scan steps in touch frames 608 in the awake state in manners similarto those described above with reference to touch frames 710 in the sleepstate (e.g., based on touch activity, the results of an SPA scan, powerconsiderations, etc.). In some examples, the above-described power-basedscan length adjustments can occur in the first low-power state, thesecond low-power state, etc., in situations in which the electronicdevice has an active state and a plurality of low-power states, aspreviously described.

It should be noted that the ranges of possible scan step lengths(“integration times”) in the different states (e.g., sleep state, awakestate, a first low-power state, a second low-power state, etc.) of theelectronic device may or may not be overlapping. In the context of thisdiscussion, a range of scan step lengths for a given operational stateof the electronic device can refer to the range from the shortest scanstep length in that operational state to the longest scan step length inthat operational state. For example, the shortest scan step length inthe awake state can be longer than the longest scan step length in thesleep state; in examples in which the electronic device has two or morelow-power states (e.g., the “sleep state” corresponds to multiplelow-power states), the ranges of scan step lengths in the multiplelow-power states can be non-overlapping with the range of scan steplengths in the awake state, though the ranges of scan step lengths inthe multiple low-power states can be overlapping with each other (e.g.,the shortest scan step length in a first low-power state can be longerthan the shortest scan step length in the second low-power state andshorter than the longest scan step length in the second low-powerstate). In some examples, the range of scan step lengths in the awakestate can partially overlap with the range of scan step lengths in thefirst low-power state, but the range of scan step lengths in the secondlow-power state may not overlap with the range of scan step lengths inthe first low-power state and/or the range of scan step lengths in theawake state—in some examples, the range of scan step lengths in thesecond low-power state may overlap with the range of scan step lengthsin the first low-power state. In some examples, the electronic devicecan have three or more operational states (e.g., awake state, firstlow-power state and second low-power state) that have ranges of scanstep lengths that do not overlap at all with each other. Other suchpermutations of ranges of scan step lengths are similarly contemplated.

In some examples, the electronic device can dynamically “gang” and“ungang” drive lines (e.g., drive lines 522 in FIG. 5) and/or senselines (e.g., sense lines 526 in FIG. 5) during scan steps 722 dependingon touch activity detected on the touch screen. In this context,“ganging” two lines together can refer to electrically connecting thetwo lines together, in parallel, such that the two lines behave,electrically, as one line. “Unganging” two lines can refer toelectrically disconnecting the two lines, which were previouslyelectrically connected in parallel, such that the two lines behave,electrically, as two separate lines. The electronic device can performsuch dynamic ganging of lines in combination with any of the scan step722 length-adjustment schemes discussed above. Further exemplary gangingand unganging details will be provided below.

FIGS. 8A-8B illustrate exemplary drive and/or sense line gangingaccording to examples of the disclosure. Specifically, FIG. 8Aillustrates touch screen 800 in which no drive lines 822 or sense lines826 are ganged together. Each drive circuitry 806 can drive its owndrive line 822, and each sense circuitry 814 can sense its own senseline 826. FIG. 8B illustrates touch screen 800 in which drive lines 822have been ganged together. For example, pairs of drive lines 822 havebeen electrically connected, in parallel, to the outputs of drivecircuitry 806. In this way, a single drive circuitry 806 can drive twodrive lines 822 connected in parallel. Though not illustrated, furtherganging of drive lines 822 can be performed, such that three or moredrive lines 822 are ganged together and driven by a single drivecircuitry 806. Additionally, sense lines 826 can similarly be gangedtogether such that a single sense circuitry 814 can sense multiple senselines 826. Such ganging of drive lines 822 and/or sense lines 826 canreduce power consumption during the sleep state, because fewer drivecircuitry 806 and/or sense circuitry 814 may need to be operating duringtouch sensing. In some examples, the electronic device may only performsuch ganging during the sleep state (e.g., during touch frames T_(S)710) and may not perform such ganging during the awake state (e.g.,during touch frames T_(A) 610). It should be noted that the examples ofthe disclosure have been provided in the context of a touch screen, butit is understood that the examples of the disclosure can similarly beimplemented in the context of a touch sensor panel.

Referring back to FIG. 7, as mentioned above, the electronic device candynamically gang or ungang the drive and/or sense lines in the touchscreen during scan steps 722. Specifically, ganging drive and/or senselines can reduce the spatial touch resolution of the touch dataresulting from scan steps 722. Therefore, the electronic device may notbe able to determine whether touch activity detected on the touch screenwhile various drive and/or sense lines are ganged corresponds to apredetermined gesture to wake the electronic device. However, it can bebeneficial for the electronic device to utilize ganged drive and/orsense lines as much as possible during the sleep state to reduce powerconsumption during the sleep state resulting from touch sensing.Therefore, in some examples, the electronic device can initially utilizescan steps 722 in which one or more drive lines or sense lines areganged together (e.g., as illustrated in FIG. 8B). Using these scansteps 722 with the ganged drive and/or sense lines, the electronicdevice can sense touch on its touch screen in the sleep state. In someexamples, if touch activity is detected on the touch screen with theseganged lines, the electronic device can reduce the ganging of its driveand/or sense lines (e.g., as illustrated in FIG. 8A) in subsequent scansteps 722 and can determine whether the touch activity is apredetermined gesture to wake the electronic device. In some examples,reducing the ganging of the drive and/or sense lines can correspond tomoving from a more-ganged configuration (e.g., three drive lines gangedtogether) to a less-ganged configuration (e.g., two drive lines gangedtogether), and in some examples, reducing the ganging of the driveand/or sense lines can correspond to moving from a ganged configuration(e.g., three drive lines ganged together) to an unganged configuration(e.g., no drive lines ganged together).

In other examples, before reducing the ganging of its drive and/or senselines in response to detecting touch activity on the touch screen, theelectronic device can first determine whether the touch data resultingfrom the ganged scan steps 722 has sufficiently high spatial resolutionsuch that the device is able to identify the touch activity, anddetermine whether it is a predetermined gesture to wake the electronicdevice. If the electronic device is able to identify the touch activityand determine whether it is a predetermined gesture to wake theelectronic device, then the electronic device can maintain the gangingof lines in scan steps 722, as is. However, if the resulting touch datahas an insufficient spatial resolution such that the electronic deviceis unable to identify the touch activity, the electronic device cangradually or incrementally reduce the ganging of its drive and/or senselines (e.g., from three ganged lines to two ganged lines, and from twoganged lines to one ganged line) until the resulting touch data has asufficiently high spatial resolution such that the device is able toidentify the touch activity on the touch screen and determine whether itis a predetermined gesture to wake the electronic device. Once theelectronic device is able to identify the touch activity on the touchscreen, it can take appropriate action (e.g., wake the electronicdevice, because the touch activity corresponds to the predeterminedgesture to wake the electronic device, or maintain the electronic devicein the sleep state, because the touch activity does not correspond tothe predetermined gesture to wake the electronic device), and in thenext touch frame T_(S) 710 during the sleep state, the electronic devicecan return to utilizing the scan steps 722 in which the initial amountof one or more drive lines or sense lines are ganged together. Theelectronic device can, then, repeat the above when subsequent touchactivity is detected on the touch screen. In some examples, theabove-described drive/sense line ganging adjustments can occur in thefirst low-power state, the second low-power state, etc., in situationsin which the electronic device has an active state and a plurality oflow-power states, as previously described.

In touch frame T_(S) 710 of FIG. 7, the electronic device can performscan steps 722 during each touch frame T_(S) 710 even when there is notouch activity detected on the touch screen of the electronic device. Itcan be beneficial to only perform scan steps 722 when some touchactivity is detected on the touch screen to reduce power consumptionduring the sleep state. FIG. 9 illustrates an exemplary touch frameT_(S) 910 of an electronic device in a sleep state (and/or during thefirst low-power state, the second low-power state, etc., in situationsin which the electronic device has an active state and a plurality oflow-power states, as previously described) that includes conditionalperformance of scan steps 922 according to examples of the disclosure.Touch frame T_(S) 910 can have a similar configuration as touch frameT_(S) 710, except as otherwise described here. In particular, touchframe T_(S) 910 can include three portions: a pre-scan portion 930, amain scan portion 932 and a sleep portion 934. During the pre-scanportion 930, the electronic device can determine whether the main scanportion 932 should be performed, as will be described below. If so, theelectronic device can perform the main scan portion 932 and then thesleep portion 934. If not, the electronic device can skip the main scanportion 932, and instead, can extend the sleep portion 934 of touchframe T_(S) 910 to the end of the pre-scan portion 930 of touch frameT_(S) 910, and the electronic device can perform the sleep portion 934.The sleep portion 934 of touch frame T_(S) 910 can comprise sleep frameT_(sleep) 918 during which no touch sensing may be performed on thetouch screen, the details of which can correspond to sleep frameT_(sleep) 718 in FIG. 7 and will not be repeated here for brevity.Exemplary details of the pre-scan portion 930 and the main scan portion932 of touch frame T_(S) 910 will now be described.

As mentioned above, during the pre-scan portion 930, the electronicdevice can determine whether the main scan portion 932 should beperformed; specifically, whether any touch activity is detected on thetouch screen. In particular, pre-scan portion 930 can includeinitialization frame T_(init) 912, during which various touch-relatedcircuitry in the touch screen can be initialized and prepared for touchscanning. For example, a touch processor and/or controller (e.g., 202and 206 in FIG. 2), drive circuitry (e.g., 306 in FIG. 3B) and/or sensecircuitry (e.g., 314 in FIGS. 3A-3B) can be initialized during T_(init)912. Pre-scan portion 930 can also include common mode scan frame T_(CM)924. In some examples T_(CM) 924 can follow immediately after T_(init)912, though other configurations are also possible. During T_(CM) 924,the electronic device can perform SPA scan 920 (e.g., as described withreference to SPA scan 720 in FIG. 7) and CM scan 928. During CM scan928, the electronic device can concurrently: 1) stimulate all of itsdrive lines with the same stimulation signal, and 2) sense all of itsense lines. The frequency at which the electronic device stimulates itsdrive lines during the CM scan 928 can be one of the low noisefrequencies detected by the electronic device during SPA scan 920. Thepurpose of CM scan 928 can be to determine whether any touch activity atall is present on the touch screen, without the need to determine anycharacteristics about the touch activity. Therefore, during the touchactivity determination frame T_(det) 926 that can follow T_(CM) 924, theelectronic device can determine if the touch data resulting from CM scan928 indicates a deviation greater than a threshold amount from baselinetouch data, which can correspond to touch data when no touch activity ispresent on the touch screen. This determination performed during T_(det)926 can be a simple comparison of raw or minimally processed touch datato baseline touch data. If the touch data resulting from CM scan 928deviates from the baseline touch data by greater than the thresholdamount, the electronic device can perform the main scan portion 932 oftouch frame T_(S) 910 (e.g., because this deviation can indicate thattouch activity is likely present on the touch screen). If the touch dataresulting from CM scan 928 does not deviate from the baseline touch databy greater than the threshold amount, the electronic device can forgoperforming the main scan portion 932, and can instead extend the sleepportion 934 of touch frame T_(S) 910 to the end of the pre-scan portion930, and can transition directly to the sleep portion 934.

The main scan portion 932 of touch frame T_(S) 910 can include touchmeasurement frame T_(burst) 914 and T_(fp) 916. T_(burst) 914 can be aperiod during which touch can be sensed on the touch screen, and caninclude scan steps 922 which can correspond to scan steps 722 in FIG. 7,the details of which will not be repeated here for brevity. Further,T_(fp) 916 can be a period during which the electronic device canprocess the touch data collected during scan steps 922 to determinewhether a particular touch input for waking the electronic device hasbeen detected on the touch screen, and can correspond to T_(fp) 716 inFIG. 7, the details of which will not be repeated here for brevity.

Because touch frame T_(S) 910 can include pre-scan portion 930, mainscan portion 932 and sleep portion 934, as described above, scan steps922 may not be performed in every touch frame T_(S) 910, and may only beperformed in touch frames T_(S) 910 in which some touch activity isdetected on the touch screen. As a result, the electronic device canconsume less power in the sleep state than it may have consumed if itoperated according to touch frame T_(S) 710 in FIG. 7. Further, theelectronic device can utilize short scan steps 922, dynamically alterthe lengths of scan steps 922, and/or gang drive and/or sense linesduring CM scan 928 and/or scan steps 922, as described above, in touchframe T_(S) 910 to further reduce power consumption during the sleepstate of the electronic device.

As mentioned above, the electronic device can utilize baseline touchdata in pre-scan portion 930 of touch frame T_(S) 910 to determinewhether any touch activity is likely occurring on the touch screen(e.g., by comparing measured touch data to the baseline touch data),where the baseline touch data can correspond to touch data when there isno touch activity on the touch screen. Similarly, during the main scan932, when the electronic device is identifying and evaluating the touchactivity on the touch screen with greater precision than in the pre-scanportion 930, the electronic device can utilize baseline touch data inorder to determine the location(s) and or amount(s) of touch on thetouch screen. Therefore, in some examples, the electronic device canhave stored in its memory such baseline touch data for use in touchframe T_(S) 910. In some examples, the electronic device can requiresuch baseline touch data for each type of scan it performs (e.g.,baseline touch data for CM scan 928, and baseline touch data for themain scan performed in scan steps 922), and for each frequency it mightutilize for each of those types of scans (e.g., each of a predeterminednumber of frequencies that SPA scan 920 can evaluate to identify a lownoise frequency at which to perform CM scan 928 and scan steps 922).

However, the actual touch data measured on the touch screen when thereis no touch activity on the touch screen can change over time due tochanges in temperature, humidity or other environmental conditions atthe electronic device. Therefore, it can be beneficial for theelectronic device to periodically update its baseline touch data.However, if the electronic device is operating according to touch frameT_(S) 910, there may be long periods of time when the main scan portion932 (e.g. a second scan type) is not triggered, because no touchactivity is detected during the pre-scan portion 930 (e.g. a first scantype) of touch frame T_(S) 910. Therefore, in some examples, theelectronic device can periodically intentionally trigger main scanportion 932 (e.g. a second scan type)—despite the electronic device notdetecting touch activity in the pre-scan portion 930 (e.g. a first scantype)—during which the electronic device can perform scan steps 922, andcan store the touch data resulting from scan steps 922 as updatedbaseline touch data for use in future scan steps 922. In the touchframes T_(S) 910 in which the electronic device intentionally triggersmain scan portion 932, the electronic device can also store, as baselinetouch data, the touch data resulting from CM scan 928 (for use asbaseline touch data in future CM scans 928). Further, in some examples,the electronic device may only trigger such a baseline-updating mainscan portion 932 if the pre-scan portion 930 indicates no touch activityis present on the touch screen, because the baseline touch data shouldcorrespond to no-touch touch data.

For example, FIG. 10 illustrates an exemplary timeline of touch frameswith intentional main scan triggering according to examples of thedisclosure. In the example of FIG. 10, a T_(S,no) 1010A touch frame cancorrespond to a touch frame in which no touch activity was detectedduring pre-scan portion 930, and the main scan portion 932 was nottriggered. A T_(S,BL) 1010B touch frame can correspond to a touch framein which no touch activity was detected during pre-scan portion 930, butthe main scan portion 932 was triggered by the electronic device inorder to gather and update its baseline touch data. Finally, a T_(S,yes)1010C touch frame can correspond to a touch frame in which touchactivity was detected during pre-scan portion 930, and therefore themain scan portion 932 was triggered by the electronic device in order toidentify and analyze the touch activity on the touch screen. Further, inthe example of FIG. 10, a T_(S,BL) 1010B touch frame can be triggeredevery three frames.

For example, in the first three touch frames T_(S,no) 1010A illustratedin FIG. 10, no touch activity is detected during the pre-scan portion930 of the touch frames. Following the first three touch frames T_(S,no)1010A in FIG. 10, the electronic device intentionally triggers touchframe T_(S,BL) 1010B to update its baseline touch data. In the nexttouch frame T_(S,no) 1010A, no touch activity is detected during thepre-scan portion 930 of the touch frame. In the next touch frame, touchactivity is detected during the pre-scan portion 930 of the touch frame,and therefore touch frame T_(S,yes) 1010C is executed. Following touchframe T_(S,yes) 1010C, no touch is detected during the pre-scan portion930 of touch frame T_(S,no) 1010A. After touch frame T_(S,no) 1010A,because it has been three touch frames since the baseline touch data waslast updated, the electronic device has intentionally triggered touchframe T_(S,BL) 1010B to update its baseline touch data. Such periodic,intentional triggering can continue in future touch frames. It isunderstood that the example of triggering a touch frame to updatebaseline touch data every three touch frames is provided as an example,only, and that other frequencies of touch frame triggering can beimplemented.

Because each frequency at which touch activity is sensed on theelectronic device can require its own baseline touch data (e.g.,no-touch touch data collected during the CM scan 928 or scan steps 922at that frequency) and because collecting baseline touch data for eachfrequency can require that a distinct baseline-update touch frame betriggered for that frequency, the number of frequencies used for touchsensing during the sleep state can be directly related to the number ofbaseline-update touch frames that may need to be triggered. However,each triggered baseline-update touch frame can consume more power than atouch frame in which the main scan portion 932 is not triggered.Therefore, it can be beneficial to reduce the number of intentionallytriggered baseline-update touch frames during the sleep state (and/orduring the first low-power state, the second low-power state, etc., insituations in which the electronic device has an active state and aplurality of low-power states, as previously described). To this end, insome examples, the electronic device can utilize fewer frequencies forsensing touch on the touch screen during the sleep state (and/or duringthe first low-power state, the second low-power state, etc., insituations in which the electronic device has an active state and aplurality of low-power states, as previously described) than during theawake state (e.g., the SPA scan 920 can scan those fewer frequencies toidentify one or more low noise frequencies, and one of those low noisefrequencies can be used during CM scan 928 and scan steps 922). Thus, insome examples, the electronic device can, during the sleep state, selectfrom a first set of candidate touch sensing frequencies for use in touchsensing, and during the awake state, select from a second set ofcandidate touch sensing frequencies for use in touch sensing, where thefirst set of candidate touch sensing frequencies includes fewercandidate frequencies than the second set of candidate touch sensingfrequencies. In some examples, over a given period of time (e.g., over acertain number of scan steps, touch frames, sleep-to-awake transitions,etc.), the electronic device will have scanned for touch using fewertouch sensing frequencies in the sleep state (e.g., using all of thecandidate touch sensing frequencies for the sleep state) than it willhave used in the awake state (e.g., using all of the candidate touchsensing frequencies for the awake state, which can be more than in thesleep state). Utilizing fewer touch sensing frequencies during the sleepstate can provide satisfactory touch sensing performance, because duringthe sleep state (e.g., when many of the subsystems of the electronicdevice, such as the display, processors, etc. can be in a low-power oroff state), fewer sources of noise, and thus fewer noise frequencies,may be present than in the awake state. As a result of utilizing fewertouch sensing frequencies during the sleep state, fewer sets of baselinetouch data may need to be tracked by the electronic device, and fewerbaseline-update touch frames may need to be triggered during the sleepstate. In some examples, these fewer frequencies can be a subset of thefrequencies used to sense touch at the touch screen during the awakestate, while in other examples, these fewer frequencies can includefrequencies both used and not used in the awake state and/or can includeonly frequencies not used in the awake state (e.g., can includefrequencies that are different than any frequency used in the awakestate).

Further, in addition or alternatively to the above, because during thesleep state the electronic device may only be trying to identify aparticular touch input (e.g., a tap), and may not require the touchdetection precision of the awake state, in some examples, the electronicdevice can update its baseline touch data less frequently during thesleep state than in the awake state. For example, in the awake state,the electronic device may trigger a baseline-update touch frame toupdate its baseline touch data once every five minutes, whereas in thesleep state, the electronic device may trigger a baseline-update touchframe to update its baseline touch data once every hour. In other words,the electronic device can determine whether it has been longer than athreshold amount of time or frames since the last time the baselinetouch data was updated, where the threshold amount of time or frames inthe sleep state can be longer than the threshold amount of time orframes in the awake state; if more time than the threshold amount oftime has passed since the last update of the baseline touch data, theelectronic device can update the baseline touch data. As such, powerconsumption during the sleep state can be further reduced. In someexamples, the above-described baseline touch data tracking adjustmentscan occur in the first low-power state, the second low-power state,etc., in situations in which the electronic device has an active stateand a plurality of low-power states, as previously described. Forexample, the electronic device can utilize a first number of frequenciesfor touch sensing during the first low-power state, and can update itsbaseline touch data for those frequencies at a first rate, and canutilize a second number (e.g., less than the first number) offrequencies for touch sensing during the second low-power state, and canupdate its baseline touch data for those frequencies at a second rate(e.g., less than the first rate). In some examples, the number offrequencies utilized for touch sensing and/or the rate at which thebaseline touch data for those frequencies is updated during the firstand second low-power states can be less than the number of frequenciesutilized for touch sensing and/or the rate at which the baseline touchdata for those frequencies is updated during the active state.

Referring back to FIG. 9, in some examples, the electronic device mayrequire that the touch input for waking the electronic device from thesleep state be detected in a specific portion of the touch screen. Forexample, the electronic device may only accept device-waking input thatis detected in the center region of the touch screen, and not around theedges of the touch screen (e.g., to prevent fingers positioned aroundthe edges of the device while a user is holding device from waking thedevice unintentionally). Therefore, in some examples, during CM scan 928in touch frame T_(S) 910, the electronic device can ignore touch datareceived by sense circuitry that sense touch within edge regions of apredetermined size of the touch screen (e.g., the left-most andright-most sense circuitry 514 in FIG. 5, or some other determinednumber of sense circuitry 514 corresponding to the left and right sidesof touch screen 500). Further, in some examples, rather than simplyignoring edge touch data, the electronic device can power-down drivecircuitry and/or sense circuitry corresponding to the edge regions ofthe touch screen during CM scan 928. FIG. 11 illustrates an exemplarytouch screen 1100 in which the drive circuitry 1106 and/or sensecircuitry 1114 corresponding to edge regions of the touch screen 1100have been powered down according to examples of the disclosure.Specifically, in some examples, the electronic device can power-downdrive circuitry 1106A corresponding to the top and bottom edges of touchscreen 1100 during CM scan 928, such that those drive circuitry 1106A donot stimulate their respective drive lines 1122 during CM scan 928.Drive circuitry 1106B corresponding to the center region of touch screen1100 can be powered-up and operate as usual (e.g., as described in thisdisclosure). Similarly, additionally or alternatively to powering-downdrive circuitry 1106A, the electronic device can power-down sensecircuitry 1114A corresponding to the left and right edges of touchscreen 1100 during CM scan 928, such that those sense circuitry 1114A donot sense touch on their respective sense lines 1126 during CM scan 928.Sense circuitry 1114B corresponding to the center region of touch screen1100 can be powered up and operate as usual (e.g., as described in thisdisclosure). In this way, touch activity at the edges of touch screen1100 can be prevented from triggering main scan 932 and/or causing theelectronic device to transition from the sleep state to the awake state.In some examples, the above-described drive/sense circuitry deactivationcan occur in the first low-power state, the second low-power state,etc., in situations in which the electronic device has an active stateand a plurality of low-power states, as previously described.

Any of the sleep state touch sensing schemes described in thisdisclosure can be used in combination with one another. Further, whichof those schemes are used together and/or the parameters of thescheme(s) used can be based on which components of the electronic deviceare powered up or operating during the sleep state (e.g., whichsub-state of a second low-power state the electronic device is in, insituations in which the electronic device has an active state and aplurality of low-power states, as previously described). For example, ifthe electronic device is playing music through a speaker during thesleep state, the speaker driver and/or other circuitry associated withthe speaker can be a source of noise for touch sensing on the touchscreen of the electronic device. Therefore, in circumstances where theelectronic device is playing audio through its speaker during the sleepstate, the electronic device can utilize main scan steps (e.g., scansteps 722 in FIG. 7 and/or scan steps 922 in FIG. 9) with greater lengthto improve the signal-to-noise ratio of the resulting touch signals, andin circumstances where the electronic device is not playing audiothrough its speaker during the sleep state, the electronic device canutilize main scan steps (e.g., scan steps 722 in FIG. 7 and/or scansteps 922 in FIG. 9) with shorter length to reduce the power consumed bythose main scan steps. Other implementations in which parameters oftouch sensing during the sleep state are adjusted based on whichcomponents of the electronic device (e.g., radio circuitry, such asWi-Fi or cellular circuitry) are powered on or operating during thesleep state, or which state or sub-state the electronic device isoperating in, are similarly contemplated. For example, a given parameterof touch sensing (e.g., such as those described above, like scan steplength, electrode ganging, drive/sense circuitry deactivation, etc.) canbe changed as the electronic device transitions from one state (e.g., anactive state) to another state (e.g., a first low-power state, a secondlow-power state, etc.).

Thus, the examples of the disclosure provide various ways for sensingtouch during a sleep state of an electronic device while maintaining lowpower consumption during the sleep state. Sensing touch during the sleepstate can be used to detect, on a touch screen or touch sensor panel ofthe electronic device, a touch input for transitioning the electronicdevice from the sleep state to an awake state.

Therefore, according to the above, some examples of the disclosure aredirected to a touch controller comprising: sense circuitry configured tosense touch at one or more touch electrodes on a touch sensor panel; anda touch processor configured to: while an electronic device is in afirst state during which a first component of the electronic device isin a first power state, cause the sense circuitry to sense touch at theone or more touch electrodes using one or more first touch scan stepshaving a first length; and while the electronic device is in a secondstate, different from the first state, during which the first componentof the electronic device is in a second power state, different from thefirst power state, cause the sense circuitry to sense touch at the oneor more touch electrodes, for transitioning the electronic device fromthe second state to the first state, using one or more second touch scansteps having a second length, shorter than the first length.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the first state comprises an awake state of theelectronic device, and the second state comprises a sleep state of theelectronic device. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the touch processor isfurther configured to, while the electronic device is in the secondstate: in response to causing the sense circuitry to sense touch at theone or more touch electrodes using the one or more second touch scansteps: in accordance with a determination that the sense circuitrysenses touch activity at the one or more touch electrodes: lengthen theone or more second touch scan steps; and determine whether the touchactivity corresponds to a touch input for transitioning the electronicdevice from the second state to the first state based on the lengthenedone or more second touch scan steps; and in accordance with adetermination that the sense circuitry does not sense touch activity atthe one or more touch electrodes, maintaining the second length of theone or more second touch scan steps. Additionally or alternatively toone or more of the examples disclosed above, in some exampleslengthening the one or more second touch scan steps comprisesincrementally lengthening the one or more second touch scan steps untilthe touch processor is able to identify the touch activity at the one ormore touch electrodes. Additionally or alternatively to one or more ofthe examples disclosed above, in some examples the touch processor isfurther configured to, while the electronic device is in the secondstate: in accordance with the determination that the sense circuitrysenses touch activity at the one or more touch electrodes, reduce anamount of ganging of the one or more touch electrodes. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the touch processor is further configured to, while theelectronic device is in the second state: determine an amount of touchsensing noise at the touch sensor panel; in accordance with adetermination that the amount of touch sensing noise is greater than anoise threshold: lengthen the one or more second touch scan steps; anddetermine whether the touch activity corresponds to a touch input fortransitioning the electronic device from the second state to the firststate based on the lengthened one or more second touch scan steps; andin accordance with a determination that the amount of touch sensingnoise is less than the noise threshold: maintain the second length ofthe one or more second touch scan steps; and determine whether the touchactivity corresponds to a touch input for transitioning the electronicdevice from the second state to the first state based on the maintainedone or more second touch scan steps. Additionally or alternatively toone or more of the examples disclosed above, in some exampleslengthening the one or more second touch scan steps comprisesincrementally lengthening the one or more second touch scan steps untilthe touch processor is able to identify the touch activity at the one ormore touch electrodes. Additionally or alternatively to one or more ofthe examples disclosed above, in some examples the touch controller isintegrated within an electronic device that comprises a touch screen,the touch screen including the touch sensor panel. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the first component of the electronic device is a display ofthe electronic device, the first power state of the display is a highpower state of the display, and the second power state of the display isa low power state of the display.

Some examples of the disclosure are directed to a touch controllercomprising: sense circuitry configured to sense touch at one or moretouch electrodes on a touch sensor panel; and a touch processorconfigured to: while an electronic device is in a first state duringwhich a first component of the electronic device is in a first powerstate, cause the sense circuitry to sense touch at the one or more touchelectrodes using a first touch sensing frequency selected from a firstnumber of candidate touch sensing frequencies; and while the electronicdevice is in a second state, different from the first state, duringwhich the first component of the electronic device is in a second powerstate, different from the first power state, cause the sense circuitryto sense touch at the one or more touch electrodes, for transitioningthe electronic device from the second state to the first state, using asecond touch sensing frequency selected from a second number ofcandidate touch sensing frequencies, less than the first number ofcandidate touch sensing frequencies. Additionally or alternatively toone or more of the examples disclosed above, in some examples the firststate comprises an awake state of the electronic device, and the secondstate comprises a sleep state of the electronic device. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the touch processor is further configured to: while theelectronic device is in the first state, store baseline touch data foreach of the first number of candidate touch sensing frequencies at afirst periodicity; and while the electronic device is in the secondstate, store baseline touch data for each of the second number ofcandidate touch sensing frequencies at a second periodicity, less thanthe first periodicity. Additionally or alternatively to one or more ofthe examples disclosed above, in some examples the baseline touch datafor each of the first number of candidate touch sensing frequencies andthe baseline touch data for each of the second number of candidate touchsensing frequencies corresponds to touch data indicative of no touchactivity. Additionally or alternatively to one or more of the examplesdisclosed above, in some examples the second number of candidate touchsensing frequencies is a subset of the first number of candidate touchsensing frequencies. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the touch controller isintegrated within an electronic device that comprises a touch screen,the touch screen including the touch sensor panel. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the first component of the electronic device is a display ofthe electronic device, the first power state of the display is a highpower state of the display, and the second power state of the display isa low power state of the display.

Some examples of the disclosure are directed to a touch controllercomprising: sense circuitry configured to sense touch at one or moretouch electrodes on a touch sensor panel; and a touch processorconfigured to, while an electronic device is in a first state duringwhich the sense circuitry senses touch at the one or more touchelectrodes for transitioning the electronic device from the first stateto a second state, wherein in the first state a first component of theelectronic device is in a first power state, and in the second state thefirst component of the electronic device is in a second power state,different from the first power state: periodically cause the sensecircuitry to perform a scan of a first scan type of the touch sensorpanel; in response to determining that a respective scan of the firstscan type of the touch sensor panel is indicative of touch activity onthe touch sensor panel, cause the sense circuitry to perform a scan of asecond scan type, different than the first scan type, of the touchsensor panel to determine whether the touch activity corresponds to atouch input for transitioning the electronic device from the first stateto the second state; and in response to determining that the respectivescan of the first scan type of the touch sensor panel is not indicativeof touch activity on the touch sensor panel: in accordance with adetermination that a first condition is satisfied, forgo causing thesense circuitry to perform the scan of the second scan type of the touchsensor panel; and in accordance with a determination that the firstcondition is not satisfied, cause the sense circuitry to perform thescan of the second scan type of the touch sensor panel to updatebaseline touch data based on the scan of the second scan type of thetouch sensor panel. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the first state comprises anawake state of the electronic device, and the second state comprises asleep state of the electronic device. Additionally or alternatively toone or more of the examples disclosed above, in some examples performingthe scan of the first scan type of the touch sensor panel comprisesperforming a single scan of the touch sensor panel; and performing thescan of the second scan type of the touch sensor panel comprisesperforming a plurality of scans of the touch sensor panel. Additionallyor alternatively to one or more of the examples disclosed above, in someexamples the first condition is not satisfied when a time since a lastupdate of the baseline touch data is greater than a threshold amount.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the touch processor is further configured to:during the scan of the first scan type of the touch sensor panel,disregard touch input sensed by sense circuitry corresponding to one ormore touch electrodes at one or more edges of the touch sensor panel.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the touch processor is further configured to:during the scan of the first scan type of the touch sensor panel, powerdown the sense circuitry corresponding to the one or more touchelectrodes at the one or more edges of the touch sensor panel.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the touch processor is further configured to:during the scan of the first scan type of the touch sensor panel, powerdown drive circuitry corresponding to one or more touch electrodes atone or more edges of the touch sensor panel. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the touch controller is integrated within an electronic devicethat comprises a touch screen, the touch screen including the touchsensor panel. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the first component of theelectronic device is a display of the electronic device, the first powerstate of the display is a high power state of the display, and thesecond power state of the display is a low power state of the display.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the touch processor is further configured to: inresponse to determining that the touch activity corresponds to the touchinput for transitioning the electronic device from the first state tothe second state, transitioning the electronic device from the firststate to the second state.

Some examples of the disclosure are directed to a method for sensingtouch on a touch sensor panel, the method comprising: while anelectronic device is in a first state during which a first component ofthe electronic device is in a first power state, sensing touch at one ormore touch electrodes on the touch sensor panel using one or more firsttouch scan steps having a first length; and while the electronic deviceis in a second state, different from the first state, during which thefirst component of the electronic device is in a second power state,different from the first power state, sensing touch at the one or moretouch electrodes, for transitioning the electronic device from thesecond state to the first state, using one or more second touch scansteps having a second length, shorter than the first length.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the first state comprises an awake state of theelectronic device, and the second state comprises a sleep state of theelectronic device. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the method further comprises,while the electronic device is in the second state: in response tosensing touch at the one or more touch electrodes using the one or moresecond touch scan steps: in accordance with a determination that thesensing senses touch activity at the one or more touch electrodes:lengthening the one or more second touch scan steps; and determiningwhether the touch activity corresponds to a touch input fortransitioning the electronic device from the second state to the firststate based on the lengthened one or more second touch scan steps; andin accordance with a determination that the sensing does not sense touchactivity at the one or more touch electrodes, maintaining the secondlength of the one or more second touch scan steps. Additionally oralternatively to one or more of the examples disclosed above, in someexamples lengthening the one or more second touch scan steps comprisesincrementally lengthening the one or more second touch scan steps untilthe touch activity at the one or more touch electrodes is able to beidentified. Additionally or alternatively to one or more of the examplesdisclosed above, in some examples the method further comprises, whilethe electronic device is in the second state: in accordance with thedetermination that the sense circuitry senses touch activity at the oneor more touch electrodes, reduce an amount of ganging of the one or moretouch electrodes. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the method further comprises,while the electronic device is in the second state: determining anamount of touch sensing noise at the touch sensor panel; in accordancewith a determination that the amount of touch sensing noise is greaterthan a noise threshold: lengthening the one or more second touch scansteps; and determining whether the touch activity corresponds to a touchinput for transitioning the electronic device from the second state tothe first state based on the lengthened one or more second touch scansteps; and in accordance with a determination that the amount of touchsensing noise is less than the noise threshold: maintaining the secondlength of the one or more second touch scan steps; and determiningwhether the touch activity corresponds to a touch input fortransitioning the electronic device from the second state to the firststate based on the maintained one or more second touch scan steps.Additionally or alternatively to one or more of the examples disclosedabove, in some examples lengthening the one or more second touch scansteps comprises incrementally lengthening the one or more second touchscan steps until the touch activity at the one or more touch electrodesis able to be identified. Additionally or alternatively to one or moreof the examples disclosed above, in some examples the electronic devicecomprises a touch screen, the touch screen including the touch sensorpanel. Additionally or alternatively to one or more of the examplesdisclosed above, in some examples the first component of the electronicdevice is a display of the electronic device, the first power state ofthe display is a high power state of the display, and the second powerstate of the display is a low power state of the display.

Some examples of the disclosure are directed to a method for sensingtouch on a touch sensor panel, the method comprising: while anelectronic device is in a first state during which a first component ofthe electronic device is in a first power state, sensing touch at one ormore touch electrodes on the touch sensor panel using a first touchsensing frequency selected from a first number of candidate touchsensing frequencies; and while the electronic device is in a secondstate, different from the first state, during which the first componentof the electronic device is in a second power state, different from thefirst power state, cause the sense circuitry to sense touch at the oneor more touch electrodes, for transitioning the electronic device fromthe second state to the first state, using a second touch sensingfrequency selected from a second number of candidate touch sensingfrequencies, less than the first number of candidate touch sensingfrequencies. Additionally or alternatively to one or more of theexamples disclosed above, in some examples the first state comprises anawake state of the electronic device, and the second state comprises asleep state of the electronic device. Additionally or alternatively toone or more of the examples disclosed above, in some examples the methodfurther comprises: while the electronic device is in the first state,storing baseline touch data for each of the first number of candidatetouch sensing frequencies at a first periodicity; and while theelectronic device is in the second state, storing baseline touch datafor each of the second number of candidate touch sensing frequencies ata second periodicity, less than the first periodicity. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the baseline touch data for each of the first number ofcandidate touch sensing frequencies and the baseline touch data for eachof the second number of candidate touch sensing frequencies correspondsto touch data indicative of no touch activity. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the second number of candidate touch sensing frequencies is asubset of the first number of candidate touch sensing frequencies.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the electronic device comprises a touch screen,the touch screen including the touch sensor panel. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the first component of the electronic device is a display ofthe electronic device, the first power state of the display is a highpower state of the display, and the second power state of the display isa low power state of the display.

Some examples of the disclosure are directed to a method for sensingtouch on a touch sensor panel, the method comprising: while anelectronic device is in a first state during which touch is sensed atone or more touch electrodes for transitioning the electronic devicefrom the first state to a second state, wherein in the first state afirst component of the electronic device is in a first power state, andin the second state the first component of the electronic device is in asecond power state, different from the first power state: periodicallyperforming scan of a first scan type of the touch sensor panel; inresponse to determining that a respective scan of the first scan type ofthe touch sensor panel is indicative of touch activity on the touchsensor panel, performing a scan of a second scan type, different thanthe first scan type, of the touch sensor panel to determine whether thetouch activity corresponds to a touch input for transitioning theelectronic device from the first state to the second state; and inresponse to determining that the respective scan of the first scan typeof the touch sensor panel is not indicative of touch activity on thetouch sensor panel: in accordance with a determination that a firstcondition is satisfied, forgoing performing the scan of the second scantype of the touch sensor panel; and in accordance with a determinationthat the first condition is not satisfied, performing the scan of thesecond scan type of the touch sensor panel to update baseline touch databased on the scan of the second scan type of the touch sensor panel.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the first state comprises an awake state of theelectronic device, and the second state comprises a sleep state of theelectronic device. Additionally or alternatively to one or more of theexamples disclosed above, in some examples performing the scan of thefirst scan type of the touch sensor panel comprises performing a singlescan of the touch sensor panel; and performing the scan of the secondscan type of the touch sensor panel comprises performing a plurality ofscans of the touch sensor panel. Additionally or alternatively to one ormore of the examples disclosed above, in some examples the firstcondition is not satisfied when a time since a last update of thebaseline touch data is greater than a threshold amount. Additionally oralternatively to one or more of the examples disclosed above, in someexamples the method further comprises: during the scan of the first scantype of the touch sensor panel, disregarding touch input sensed by sensecircuitry corresponding to one or more touch electrodes at one or moreedges of the touch sensor panel. Additionally or alternatively to one ormore of the examples disclosed above, in some examples the methodfurther comprises: during the scan of the first scan type of the touchsensor panel, powering down the sense circuitry corresponding to the oneor more touch electrodes at the one or more edges of the touch sensorpanel. Additionally or alternatively to one or more of the examplesdisclosed above, in some examples the method further comprises: duringthe scan of the first scan type of the touch sensor panel, powering downdrive circuitry corresponding to one or more touch electrodes at one ormore edges of the touch sensor panel. Additionally or alternatively toone or more of the examples disclosed above, in some examples theelectronic device comprises a touch screen, the touch screen includingthe touch sensor panel. Additionally or alternatively to one or more ofthe examples disclosed above, in some examples the first component ofthe electronic device is a display of the electronic device, the firstpower state of the display is a high power state of the display, and thesecond power state of the display is a low power state of the display.Additionally or alternatively to one or more of the examples disclosedabove, in some examples the method further comprises: in response todetermining that the touch activity corresponds to the touch input fortransitioning the electronic device from the first state to the secondstate, transitioning the electronic device from the first state to thesecond state.

Although examples of this disclosure have been fully described withreference to the accompanying drawings, it is to be noted that variouschanges and modifications will become apparent to those skilled in theart. Such changes and modifications are to be understood as beingincluded within the scope of examples of this disclosure as defined bythe appended claims.

1. A touch controller comprising: sense circuitry configured to sensetouch activity at one or more touch electrodes on a touch sensor panel;and a touch processor configured to: while the electronic device is in afirst power state, during which a first component of the electronicdevice is in a first power state: cause the sense circuitry to sense theone or more touch electrodes using one or more first touch scan stepshaving an initial scan length; and in accordance with a determinationthat the sense circuitry senses touch activity at the one or more touchelectrodes: in accordance with a determination that the touch activitysatisfies one or more power state transition criteria, transition theelectronic device from the first power state to a second power state,during which the first component of the electronic device is in a secondpower state, different from the first power state; and in accordancewith a determination that the touch processor cannot determine whetherthe touch activity satisfies the one or more power state transitioncriteria, increase a scan length of one or more subsequent touch scansteps to a second scan length, longer than the initial scan length,while remaining in the first power state.
 2. The touch controller ofclaim 1, wherein the one or more power state transition criteria includea requirement that the touch activity matches a predetermined gesture.3. The touch controller of claim 1, wherein the touch processor isfurther configured to: after increasing the scan length of the one ormore subsequent touch scan steps to the second scan length, determinethat subsequent touch activity satisfies the one or more power statetransition criteria; and in response to determining that the touchactivity satisfies the one or more power state transition criteria,transition the electronic device from the first power state to thesecond power state.
 4. The touch controller of claim 1, wherein thetouch process is further configured to: after increasing the scan lengthof the one or more subsequent touch scan steps to the second scanlength, determine that subsequent touch activity does not satisfy theone or more power state transition criteria; and in response todetermining that the touch activity does not satisfy the one or morepower state transition criteria, maintain the electronic device in thefirst power state.
 5. The touch controller of claim 1, wherein the touchprocessor is further configured to incrementally increase the scanlength of the one or more subsequent touch scan steps until the touchprocessor is able to determine whether the touch activity satisfies theone or more power state transition criteria.
 6. The touch controller ofclaim 5, wherein: while the electronic device in the second power state,the sense circuitry scans the one or more touch electrodes using one ormore respective touch scan steps having a respective scan length; and amaximum scan length of the one or more subsequent touch scan steps isthe respective scan length.
 7. The touch controller of claim 5, wherein:while the electronic device in the second power state, the sensecircuitry scans the one or more touch electrodes using one or morerespective touch scan steps having a respective scan length; and amaximum scan length of the one or more subsequent touch scan steps islonger than the respective scan length.
 8. The touch controller of claim1, wherein the touch processor is further configured to: before causingthe sense circuitry to scan the one or more touch electrodes using theone or more first touch scan steps having the initial scan length: causethe sense circuitry to sense the one or more touch electrodes; inaccordance with a determination, based on the sensing of the one or moretouch electrodes, that a noise level is above a threshold noise level,set the initial scan length to a first scan length; and in accordancewith a determination, based on the sensing of the one or more touchelectrodes, that the noise level is below the threshold noise level, setthe initial scan length to a second scan length, less than the firstscan length.
 9. The touch controller of claim 1, wherein the touchprocessor is further configured to: in accordance with the determinationthat the sense circuitry senses touch activity at the one or more touchelectrodes: in accordance with a determination that the touch activitydoes not satisfy the one or more power state transition criteria,maintain the electronic device in the first power state.
 10. A methodfor sensing touch on a touch sensor panel, the method comprising: whilethe electronic device is in a first power state, during which a firstcomponent of the electronic device is in a first power state: sensingthe one or more touch electrodes using one or more first touch scansteps having an initial scan length; in accordance with a determinationthat the sense circuitry senses touch activity at the one or more touchelectrodes: in accordance with a determination that the touch activitysatisfies one or more power state transition criteria, transitioning theelectronic device from the first power state to a second power state,during which the first component of the electronic device is in a secondpower state, different from the first power state; and in accordancewith a determination that the touch processor cannot determine whetherthe touch activity satisfies the one or more power state transitioncriteria, increasing a scan length of one or more subsequent touch scansteps to a second scan length, longer than the initial scan length. 11.The method of claim 10, wherein the one or more power state transitioncriteria includes a requirement that the touch activity matches apredetermined gesture.
 12. The method of claim 10, further comprising:after increasing the scan length of the one or more subsequent touchscan steps to the second scan length, determining that the touchactivity satisfies the one or more power state transition criteria; andin response to determining that the touch activity satisfies the one ormore power state transition criteria, transitioning the electronicdevice from the first power state to the second power state.
 13. Themethod of claim 10, further comprising: after increasing the scan lengthof the one or more subsequent touch scan steps to the second scanlength, determining that subsequent touch activity does not satisfy theone or more power state transition criteria; and in response todetermining that the touch activity does not satisfy the one or morepower state transition criteria, maintaining the electronic device inthe first power state.
 14. The method of claim 10, further comprisingincrementally increasing the scan length of the one or more subsequenttouch scan steps until the touch processor is able to determine whetherthe touch activity satisfies the one or more power state transitioncriteria.
 15. The method of claim 14, wherein: while the electronicdevice in the second power state, the sense circuitry scans the one ormore touch electrodes using one or more respective scan steps having arespective scan length; and a maximum scan length of the one or moresubsequent touch scan steps is the respective scan length.
 16. Themethod of claim 14, wherein: while the electronic device in the secondpower state, the sense circuitry scans the one or more touch electrodesusing one or more respective scan steps having a respective scan length;and a maximum scan length of the one or more subsequent touch scan stepsis longer than the respective scan length.
 17. The method of claim 10,further comprising: before causing the sense circuitry to scan the oneor more touch electrodes using the one or more first touch scan stepshaving the initial scan length, causing the sense circuitry to sense theone or more touch electrodes; in accordance with a determination, basedon the sensing of the one or more touch electrodes, that a noise levelis above a threshold noise level, setting the initial scan length to afirst scan length; and in accordance with a determination, based on thesensing of the one or more touch electrodes, that the noise level isbelow the threshold noise level, setting the initial scan length to asecond scan length, less than the first scan length.
 18. The method ofclaim 10, further comprising: in accordance with the determination thatthe sense circuitry senses touch activity at the one or more touchelectrodes: in accordance with a determination that the touch activitydoes not satisfy the one or more power state transition criteria,maintaining the electronic device in the first power state.